Diseases & conditions A-Z List

Diseases & Conditions A-Z List - «R»:

Renal perfusion scintiscanA renal perfusion scintiscan is a nuclear medicine test that uses a small amount of a radioactive substance to create an image of the kidneys.
How the Test is Performed
Before the scan, you will be asked to drink plenty of water so that you stay hydrated and to take a blood pressure medicine called...

Renal scanA renal scan is a nuclear medicine exam in which a small amount of radioactive material (radioisotope) is used to measure the function of the kidneys.
How the Test is Performed
The specific type of scan may vary, depending on the patient's specific needs. This article provides a general overview.
A...

Renal vein thrombosisRenal vein thrombosis is a blood clot that develops in the vein that drains blood from the kidney.
Causes
Renal vein thrombosis is a fairly uncommon situation that may happen after trauma to the abdomen or back, or it may occur due to:
Scar formation
Stricture
Tumor
It may be associated with ne...

Renal venogramA renal venogram is a test to look at the veins in the kidney. It uses x-rays and a special dye (called contrast).
X-rays are a form of electromagnetic radiation like light, but of higher energy, so they can move through the body to form an image on film. Structures that are dense (such as bone) wil...

ReninRenin is a protein (enzyme) released by special kidney cells when you have decreased salt (sodium levels) or low blood volume.
Renin also plays a role in the release of aldosterone, a hormone that helps control the body's salt and water balance.
A test can be done to measure the amount of renin in y...

Renovascular hypertensionRenovascular hypertension is high blood pressure due to narrowing of the arteries that carry blood to the kidneys.
See also:
Atheroembolic renal disease
Hypertension
Malignant hypertension
Causes
When the arteries that carry blood to your kidneys become narrow, less blood flows to the kidne...

Repair of webbed fingers or toesRepair of webbed fingers or toes is surgery to fix webbing of the toes, fingers, or both. The middle and ring fingers or the second and third toes are most often affected.
Description
This procedure is done using general anesthesia. The patient is asleep and pain-free.
The health care provider will...

Repeated nightmaresRepeated nightmares are bad dreams that recur frequently and involve the same theme.
Nightmares usually begin before the age of 10 and are considered a normal part of childhood, unless they significantly interfere with sleep, physical development, or psychosocial development. They tend to be more co...

Reportable diseasesReportable diseases are diseases considered to be of great public health importance. Local, state, and national agencies (for example, county and state health departments or the U.S. Centers for Disease Control and Prevention) require that such diseases be reported when they are diagnosed by doctors...

ResourcesFor information, resources, and support on specific diseases and conditions, see the links below. Additional local and national support groups can be found on the web, through local libraries, your health care provider, and the yellow pages under "social service organizations."
AIDS - resources
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Respiratory acidosisRespiratory acidosis is a condition that occurs when the lungs cannot remove all of the carbon dioxide the body produces. This disrupts the body's acid-base balance causing body fluids, especially the blood, to become too acidic.
Causes
Causes of respiratory acidosis include:
Diseases of the airwa...

Respiratory alkalosisRespiratory alkalosis is a condition marked by low levels of carbon dioxide in the blood due to breathing excessively.
See also: Alkalosis
Causes
Common causes include:
Anxiety
Fever
Hyperventilation
Any lung disease that leads to shortness of breath can also cause respiratory alkalosis.
Sympt...

Respiratory syncytial virus (RSV)Respiratory syncytial virus (RSV) is a very common virus that leads to mild, cold-like symptoms in adults and older healthy children. It can be more serious in young babies, especially to those in certain high-risk groups.
Causes
RSV is the most common germ that causes lung and airway infections in...

Restless leg syndromeRestless leg syndrome is a disorder in which there is an urge or need to move the legs to stop unpleasant sensations.
Causes
Restless leg syndrome (RLS) occurs most often in middle-aged and older adults. Stress makes it worse. The cause is not known in most patients.
RLS may occur more often in pat...